Efficient and successful farming operations require careful cultivation of the soil between the rows of planted or growing crops. For example, the soil must be aerated or rearranged and residues from prior crops remaining in the field cut or mulched. Weed population must be controlled by uprooting or cutting beneath the ground level. Such cultivation procedures become particularly important in ridge-till and minimum tillage farming. In ridge-till farming, seeds are planted in rows of soil ridges that leave depressions or valleys between the ridges. With normal weathering, particularly under rainy or muddy conditions, soil from the ridges tends to wash down into the valleys and must be piled back to the ridges. In minimum tillage farming involving plants with light root systems, such as soybeans, the rows of seeds are planted without deep plowing or tillage so that the weeding and the removal of prior crop residues are important.
A variety of agricultural implements have heretofore been provided for carrying out cultivating procedures of the type alluded to. In general, such implements comprise an elongated, transverse frame or tool bar, adapted to be towed by a tractor or the like. Mounted from the frame are a plurality of similar earth-working tools, such as rotating harrow disks, coulters, tines, chisels, spikes, shovels, or the like. The tools are appropriately spaced on the frame so that the cultivator implement can be drawn through the field and the tools do their intended work on the soil between the rows of seeds or growing crops.
Frequently, the earth-working tools comprise individual units which are ganged on an elongated frame. Since field and soil conditions are constantly changing, provision must be made for maintaining relatively constant operating depth control of the individual cultivator tool units. For this purpose, it is known to provide individual cultivator units with spring-loaded parallel linkage support arrangements that automatically maintain tool depth control in response to varying field conditions. Examples of such parallel linkage arrangements are shown in U.S. Pat. Nos. 4,356,780; 4,373,456; 4,398,478 and 4,423,788, for use in connection with a somewhat related but different implement, a seed planter.
The cited patents give some indication of the difficulty of dealing with the depth control problem as it relates to the isolated seed planting operation. Depth control becomes an even more complex problem when all of the variables relating to cultivating prior crop residues and weeds are added to those of mere soil conditions. Typically, a ridge-hill or minimum tillage cultivator unit will comprise a number of different tools, such as soil movers, coulters and sweeps, so that the combined functions of those tools can be utilized during a single pass through the field. Many tool and depth control adjustments are required to be made in the field. With prior known cultivators, such field adjustments were difficult to make, time-consuming and frequently required the use of tools.
Thus, there exists a need for a row crop cultivator that is capable of performing a number of cultivator functions and yet is easily and readily adjustable as field and crop conditions dictate. Desirably, the adjustments should not require the use of tools or wrenches, but should yet provide a broad and substantial number of incremental adjustments.